Asystem of equations is shown below:

y = 5x + 3
y = 4x + 6

what is the solution to the system of equations?

a) (−3, 18)
b) (−3, −18)
c) (3, −18)
d) (3, 18)

To answer the question above, use substitution. The method involves substituting y of the second term by the expression for y in terms of x of the first term. This is shown below. 
 
                                     (1)        y = 5x + 3
                                     (2)        y = 4x + 6

Substituting, 
                                           5x + 3 = 4x + 6

Solving for x in this equation gives x = 3. Use this value to solve for y in any of the equations, 
 
                                             y = 5(3) + 3 = 18

Therefore, the answer is letter "D. (3, 18)".